Bacteriological profile and antimicrobial susceptibility pattern of sputum samples in patients presenting to the pulmonology ward of a tertiary care hospital of Peshawar

Abstract

Introduction: Pathogens causing respiratory infections keep changing, and a wide array of pathogens are implicated as causative agents. This diversity has imposed a challenge for clinicians to establish a specific etiological diagnosis and initiate the most suitable antimicrobial therapy.
Objective: To document the most common bacteriological organisms detected from sputum culture in patients presenting to the Pulmonology ward of Rehman Medical Institute (RMI) and determine their antimicrobial sensitivity patterns.
Materials & Methods: Sputum culture of 50 patients presenting to the pulmonology department from 2016-2017 were collected in the lab after informed consent. Anti-microbial susceptibility testing of microbial isolates was performed according to the guidelines issued by the National Committee for Clinical Laboratory Standards. Different antimicrobials were used for different pathogens based on the type of resistance and availability. Growth of the microbe was inhibited around discs containing antimicrobials agents to which it was susceptible but not around those to which it was resistant.
Results: The most commonly isolated pathogen was Pseudomonas species (n=12) followed by Escherichia coli (n=10), and Staphylococcus aureus (n=7). Gram negative bacteria made up 78% and gram positive bacteria 22% of the pathogens. Pseudomonas species was susceptible to most of the drugs and showed resistance towards Aztreonam (36.36%) and Ciprofloxacin (33.33%). It showed (100%) susceptibility to colistin and meropenem. Escherichia coli was 100% resistant towards Amoxicillin, Ampicillin, Ciprofloxacin, Cefotaxime, and Doxycycline. Least resistance was seen to Piperacillin/Tazobactam (55%), Cefoxitin (33.33%), Imipenem (20%) and Gentamicin (25%).
Conclusions: Varying patterns of resistance of pathogens towards commonly used antimicrobial agents existed, with most pathogens being resistant to third generation Cephalosporins and extended spectrum Penicillins.